Effect of Bentonite Clay on the Mechanical, Thermal, and Pervaporation Performance of the Poly(Vinyl alcohol) Nanocomposite Membranes

Bentonite clay/poly(vinyl alcohol) (PVA) inorganic/organic hybrid nanocomposite membranes were prepared via solvent casting method. A series of PVA nanocomposite membranes have been prepared by varying the concentration of the bentonite clay. Nanoscale dispersion of bentonite clay affected the properties of PVA. PVA with 5 wt % clay showed better enhancement in the properties. Both X-ray diffration and transmission electron microscopy showed uniform dispersion and exfoliated structure of the bentonite in the PVA membranes. The effective separation of azeotropic composition of isopropanol (IPA) and water mixtures was also carried out by using these membranes. The flux and separation factor of the membranes were increased with 1 wt % clay loading and followed by a decrease. The intrinsic properties of the membranes have been calculated using membrane permeance and selectivity. The 1 wt % clay loaded membrane showed enhanced membrane permeance with a water permeance of 6500 gpu and a selectivity value of 46. The effective membrane area for transport has been analyzed from atomic force microscopy analysis. Finally, it is important to mention that the minimum nanoscale filler loading gave rise to the maximum separation efficiency for the azeotropic composition of IPA and water mixtures.